Telephone-receiver.



Hl Rl' y TELEPHONE RECEIVER. l APPLIULTION FILED KAREL 1908.

977,981. Patented Dec. e,191.

" To all lwhom 'it may concern:

v'citizen' of the United States, residing NTE iSTATS 'HARVE R. STUART, 0F W-HIEIELIIYI'GI; WEST VIRGINIA.

' TELEPHONE-RECEIVER..

Be it known that I, HARVE R. STUART, a -at Wheeling, inthe county of Ohio and State of West Virginia, have invented certain new and useful Improvements. in Telephone-Receivers, .of which the following is 'a full, clear, and e act description.

My inven ionV relates to telephone receivers for general use in telephonie circuits, and more particularly designed for use in connection with telegraphones, and has for its object the production of a receiver characterized by Improved features of mechanical construction and magnetic arts so arranged and combined mechanica y and magnetically as to -produce a receiver sensitive to feeble or small currents and capable of producing strong acoustic effects.

My invention consists in the features hereinafter described and claimed.

of receiver with the .dia

Reference is hereby made to the accompanying drawing, in which the 'same reference numerals are used to desi ate corresponding parts. in `the severa views, of

Figure `1 is a plan of the lower half of the receiver with the diaphragm removed, showing the shape of the lower magnet and its supporting casing; Fig. 2 is a section ofthe complete evice on line 2-2fof. Fig. 1; Fig.

43 is a side elevation of the receiver;-Fi1g. 4 in ing isa sectional detail f one of the b posts and a portion of the casing; Fig. 5 .is a plan of-.the lower half of: a modified form hragmV removed; ine 6 6 of Fig. 5.

and Fig. 6 is a section on comprises -a' casmg "The recelver shown formed `of the oppositely disposed pupd shaped, members. 2 and 3, of non-magnetic ymaterial, having horizontal flanges 4 and V5,

respectively which are held. togethe'r by securing screws 6, the diaphragm 7 'of mag-' netic material suehas iron being' clamped between said flanges 4 and. 5, and rmly held thereby. The members 2and 3.are each provided with a sound conveying tube 8, to which ear pieces, megaphoes or listening tuberi may be applied. The members 2- an 3 are .provided with magnets 9" and 10: respectively and which are preferably permanent magnets, although electromagnets may be used if desired. Thesepmagnets are' of peculiar shape, shown clearly-in Fig. 1, be-

Specicaton offIetters Patent. Application ledJIarch 21, 1908.- Serial No. 422,397.

strengthened; when Patented Dec. 6, 1910.

ing the form of a 'ring with inwardly extending arms 11, ca'rry1ng the pole pieces 12 which extend in a direction perpendicular to the plane of the ring. While the ring- Y shaped magnets are' preferably circular in outline, I contemplate the use of other forms of; ring by which I mean a closed fi ure of any form. Surrounding the' pole pieces are the .coils currents pass. The magnets 9 and l() are preferably so disposed as to bring like oles opposite each other, that is, the N po e of ma et 9 is, opposite the N pole of magnet liiit may be disposed so as to bring unlike polesopposite each other, or the plane of the pole pieces of one magnet may be at right angles tothe plane of the pole pieces of the other magnet. In each case, the coils 13 'are so woundjthat a current. passing through the same in one direction tends to weaken the field of one of the magnets, and at the same time to strengthen the field of the other`magnet, whereby the diaphra 7 is 'moved toward-the magnet whose iie d is a current passes through the coils 13 in the Opposite direction, the diaphragm will be attracted or moved to- .ward` the other magnet. The receiver is therefore a balanced receiver, since the diaphragm or armaturels normally attracted ymagnets of substantially equal strength acting 1n opposite directions, the voice cur- 'rents strengthening one magnet and simultaneously.- weakening the other magnet in alternation. Y 'I lhe magnetsv 9 and 10 are secured to thel casmg members by screws 14, rings 15 of yielding or resilient material such a\s soft rubber, being preferably interposed between e'magnets vand the casing, so that the gap between the pole pieces ing the screws 14 toeompress the said rings. The casing is dividedby the diaphragm 7 into two resonance chambers 16 and 17, within which 'the magnets are' situated, and which are in unobstructed communication with the sound-conveying tubes 8. The four coils 13 may-be connected together either 1n series or in-multiple or in series-multiple as desired'. The current may be aaplplied to the windings-of the coils from bin 'ng posts of any. suitable form, aheaded bolt 18 th length ofthe air all. diaphragm may be increased by tightenthat shown consisting ofl which passes through insu-- 13, through which the voice.'

lating bushin s 19 and 20, which are clamped to the casing y the nut 21, threaded on said bolt. A conducting plate 22, also surrounds said bolt 18 and is rigidly held thereby, said plate beino provided with a binding screw 23 threadetd therein.

In the modication illustrated in Figs. 5 and 6, each of the magnets comprises a plate 24, which is secured b screws l25 to the cupshaped members 2 an 3 respectively, which are of non-magnetic material. The said plates 24 have inwardly extending arms 26 to which is secured a plate 27 by screws (not shown) and to the center of said plateis secured a pole piece 28 which extends at right angles Ato the plane of the late 24 with its free end in'proximity to t e center of the diaphragm 7. A coil 29 surrounds the ole piece 28 and is connected with the bin 1n posts 30 for receivin the voice currents an varying the flux o the magnetic circuit. Each magnet also comprises a pair of curved plates 3l disposed opposite each other and secured to the edges of the plates 24. The edges of said curved plates make contact with the diaphragm 7, when the casing members 2 and 3 are secured together by the bolts 6. (See Fig. 3). In this construction, the diaphragm forms a part of the magnetic 30 circuit, the lines of force passing throu h the same from its center toward its perip ery, or viceversa. The pole pieces 28 of the two magnets are preferably of the same polarity, and the coils 29 are so wound that a current iowing in onedirection tends to weaken the magnetic liux of one of the magnets, at the same time strengthening the flux of the other magnet, and a current 1n the opposite direction strengthens the liux of the rst magnet and weakens that of the second. This receiver is also a balanced receiver, as explained in connection with the receiver of Figs. 1-4, and is small, light and compact.

,Having nowV described my invention, what I claim, is

l. In a receiver, a diaphragm a pair of magnets each in the form of a ring having inwardly extending lilleted arms, and pole pieces extending from said arms transversely to the plane of the ring, the pole pieces of one magnet being opposite the ,pole

pieces of the other magnet; adjacent pole pieces of the two magnets being of similar "ipolarity and disposed4 upon opposite sides of f'said diaphragm.

2. In a receiver, a pair of magnets each in the form of a ring having inwardly eX- tending'arms, pole pieces extendin from said arms transversely to the plane o the ring,

the pole pieces of one magnet being opposite vthe pole pieces of the other magnet and adjacent pole pieces of the two magnets being of similar polarity, and a diaphragm situated between the pole pieces of one magnet and the pole pieces of the other magnet.

3. In a receiver, the combination of a hollow casing, a dlaphragm secured thereto, a magnet having a pole 1n proximity to the ,center of thediaphragm, a second magnet having a ole in proximity to the center of the opposite face of the diaphragm, a resilient member interposed between each of said magnets and the casing, and means for compressing said resilient means for varying the length of the air gap between each magnet and the diaphragm.

4. In a receiver, the combination of a hollow casing, a diaphragm secured thereto, a magnet having a pole in proximity to the center'of the diaphragm, a second magnet 80 having a pole in proximity to the center of the opposite face of the diaphragm, a member interposed between each of said magnets and the easing, and means for actuating said member for varying the length ofthe air gap between each magnet and the diaphragm.

5. In a receiver, the combination of a cupshaped casing member having a central sound orifice, a magnet within said member and comprising a flat plate having openings therethrough, a resilient ring interposed between said magnet and said casing member, 'and means -for drawing said magnet and casing member together.

6. In a receiver, the combination of a hollow casing, a' diaphragm extending across the same so as to form a pair of sound chambers, each of which has a sound orice, and a magnetl situated within each of said sound chambers and having a pole in roximity to the center of the diaphragm, said magnets being of such a strength and distance from the diaphragm that their attractions are normally balanced, whereby the diaphragm is practically unstressed.

7. In a receiver, the combination of a hollow casing, a diaphragm secured therein and dividing said casing into two sound chambers, each of which has a sound orifice, magnets each comprising a liat plate and a pole piece extending at right angles thereto into proximity to the center of the diaphragm, said magnets being of suchy a strength and distance from the diaphragm that their attractions are normally balanced, whereby 115 the diaphragm is practically unstressed.

8. In a receiver, thel combination of a hollow casing, a diaphragm secured therein to form a sound chamber havin a sound orillO tice, a magnet comprising a at plate and a pole piece extending atright angles thereto into proximity to the center of` the diaphragm, and 'means for adjusting said magnet toward and away from said diaphragm and a similar magnet arranged close to the opposite face of the diaphragm at such a distance that the attraction thereof balances the attraction of said first magnet.

9. In a receiver, the combination of a simt ple diaphragm, free from connection .with

other vibrating parts, a magnet having its so that their respective like poles are opporespective poles adjacent to one face of said site each other. 10

vdiaphragm neer the center thereof, and an- In Witness whereof, I Subscribe my signaotherv magnet having its respective poles sufture, in the presence of two Witnesses. fciently close to the opposite side of said HARVE R. STUART. diaphragm, near the center thereof, to Witnesses:

,balance the attraction of the magnet first FRANK AS. OBER,

mentioned, the two magnets being arranged WALDo M. CHARM?. 

